I have read several accounts of this, but were there actual Night Bomber regiments of B-25, or as intruders? and when did they begin operating? I know that ZuSayn-Wittgenstein made several claims in 1943.

Yes, soviet B-25s were regularly used for night bombing and supply drop purposes in 1944-45. One of their most famous mission-series was the supply drop missions over Yugoslavia for Tito partizans with several losses in 1944: 42-87490 red '2', 42-32474 red '12', 43-3507 red '4', etc.

18 VA also used 14., 238., 251. GvBAPs for night bombings over Hungary and Austria in 1945...

In late August 1941 a prestigious Soviet AF delegation arrived by two GST flying boats via Alaska in USA for study and selection of much demanded heavy bombers to be delivered to USSR. The delegation led by the test pilot M.M.Gromov was prepared to ferry the selected aircraft back to USSR as soon as possible. Their first preference was the B-17 (which was absolutely refused by the Americans). On 16 September 1941 the Soviets agreed to three B-26 Marauders and two B-25B Mitchells, after rejecting the B-25A because of insufficient defensive armament. Two weeks later the Soviets finally settled for five B-25Bs (to which the B-26 was considered to be inferior). Before delivery of the B-25B installation of additional de-icing equipment was requested. (American accounts stress the difficult negotiations with the Soviets who repeatedly changed their preferences and presented requests for additional modifications, equipment and spares.)

As the range of the B-25B was considered insufficient for the long ferry flight to Russia, the first two B-25B were shipped out of USA 6 November 1941, and arrived in Murmansk 20 December on board convoy PQ-6. Only on 5 March 1942 both aircraft arrived in Moscow. One of the first B-25B served later as personal transport of I.P.Mazuruk, C.O. of 1 PIAD, with both red stars and semi-civil code "URSS".

Major deliveries of Mitchells commenced in spring 1942 via Abadan, Iran. The first operational Mitchells were allocated to 37 BAP of 222 BAD, and soon also the other two regiments, 16 and 125 BAP of this division were equipped with Mitchells. At first this division belonged to the short-lived 1 BAA (Bomber Aviation Army), but in July 1942 the division became part of the Reserve of the Supreme Command (RBGK). After rather heavy initial losses, the - in Soviet eyes - rather big Mitchell bomber was considered more suitable for night operations, and in 29 September 1942 222 BAD was transferred to ADD. In order to ensure the range required by ADD, additional fuel tanks were installed. Late autumn 1942 a continuous flow of Mitchells arrived via the ALSIB-route, enabling expansion of the 222 BAD (which meanwhile, 26 March 1943 had been elevated to 4 GAD) into the 4th Aviation Corps (4 GAK) on 3 July 1943. 4 GAK became the main Soviet Mitchell-operator, consisting of two divisions, 4 and 5 GAD, with two regiments each. In winter 1943-44 a third regiment were added to the ADD divisions. Consequently a detached regiment, 113 AP NOB (which on 10 January 1944 became 27 GAP NOB, and which was mainly equipped with heavy A-20G Boston night-fighters in addition to Mitchells) was also added to the structure of 4 GAK.

4 GAK participated in almost all major operations of the Red Army in 1943-1945, and played also a significant role in the strategic bombing attacks against Helsinki in February 1944. In autumn 1944 5 GAD supported the capture of Belgrad, and five pilots from this division were decorated as Heroes of Yugoslavia.

In autumn 1944 ADD supported the Slovakian uprising with an air bridge consisting of Li-2, C-47 and B-25 Mitchell aircraft. B-25s of 4 GAK dropped supplies to the Tri Duby airfield in central Slovakia from the night of 4/5 September 1944. In the night of 26/27 September the Mitchells were joined by Li-2s and C-47s of 5 AK (see Li-2/C-47 section). 4 GAK performed a total of 498 missions (of which 352 successful) with B-25 bombers, transporting 253 tons of arms and ammunition to the insurgents for the loss of of one aircraft before Tri Duby had to be evacuated.

All other ADD aviation corpses (except 2 GAK) used also smaller numbers of Mitchells. In early 1944 Mitchells amounted to approx. 10 % of all ADD aircraft, and on 1 January 1945 ADD-successor 18th Air Army had 320 Mitchells, or about one fifth of its total strength. (After the reorganisation of ADD as 18th Air Army on 6 December 1944, the ADD Guards regiments and divisions were renumbered in order to "fit" into the VVS numbering scheme.)

At the end of the war a number of Mitchells equipped with S-1 autopilots and Norden M-9 bombsights were also delivered to Russia (the top-secret and restricted Norden system had for a long time been on the top of the Soviet “want list”). As a big number of German Lotfe-7 systems were captured in East Germany possible replacement of the Norden bombsights with Lotfe-7 equipment was studied in late 1945 (obviously because of lack of spares for the US equipment), however resulting in directional instability of the aircraft.

Mitchells performed also long-range recce tasks in various VVS and naval regiments. In particular the strategic recce regiments of the Soviet Supreme Command 48 GDRAP (ex 40 DRAP) and 98 GDRAP (ex 4 DRAP) used a number of specially equipped Mitchells.

A number of force-landed USAAF Mitchells were taken over by 128 SAD in the Far East. The first Mitchell interned at Vladivostok was B-25B 40-2242, which had participated in the legendary Doolittle Raid to Tokio 18 April 1942.

On 12 September 1942 a total of seven US bombers, apparently five B-25 Mitchells and two B-24 Liberators landed at Yelizovo, Kamchatka. The B-25 Mitchells were led by Major Richard de Syuge, and included B-25C-10-NA 42-53352 piloted by Lt. Rodgen. 51 American aviators were interned, and the aircraft detained.

Although considerable numbers of lend-lease aircraft were destroyed 1945-47 under the supervision of American inspectors, Mitchell bombers were nevertheless extensively used for several years after the war. Eg. the Bobrujsk-based 330 BAP used Mitchells from 1946 until conversion to Tu-4s started in 1949, the Sakhalin-based 132 BAP converted from Tu-2s to B-25J Mitchells in 1950, and a Kamchatka-based regiment operated Mitchells still in 1953. In the early 1950s the test-pilots school (Shkola letchikov-ispytatelej) at Kratovo (now Zhukovskiy) had still a number of B-25 Mitchells in its inventory. As late as 1951 the Dal´nyaya Aviatsiya-regiment 121 GTAP converted to recce-modified B-25 Mitchells, the regiment simultaneously receiving the denomination 121 GODRAP (121 Guards Detached Long-Range Recconnaissance Aviation Regiment). 121 GODRAP used B-25s until 1953 when new Tu-4s were received.

Because of the good piloting characteristics and strong structure permitting extensive modifications the Mitchell was a very popular test-bed for various R&D projects in the late 1940s, including - flight testing of early jet engines (eg. the Jumo 003-copy RD-10F), and D-5 and D-6 ram-jets,- development of air-to-air tanking methods, - testing of rocket-assisted take-off with “93-1” powder and SU-1500 liquid rockets,- catapult experiments,- testing of the ejectable pilot capsule of the experimental German rocket aircraft “346” at LII in 1948,- development of Shchuka gliding torpedos at Yevpatoriya in 1947-1948 etc.

A number of these experimental Mitchell modifications are illustrated in the pictorial section, but it seems that this interesting aspect of the Mitchell-history in Russia is still insufficiently documented.

Several Mitchells were also converted to VIP-transports (users including NII VVS, C.O. of Naval Air Forces, Ministry of Fishing etc.). After the war some demilitarised Mitchells were also entered into the civil register and used eg. as courier aircraft by 2 AD GVF and as VIP-passenger aircraft.

A total of 877 Mitchells of various subtypes were received in USSR (another nine were lost in transit).

1 January 1945 the inventory of 18 Air Army (ex-ADD) included 291 B-25 Mitchells, of which 252 remained 12 June 1946 in the inventory of Dal’nyaya aviatsiya (DA).

To my knowledge there were several successful and unsuccessful Tito's partizans support missions one of which was on Aug 25,44 from Balti over Yugoslavia ending up in Bari perfomed
with A-20's from 861st BAP ... The mission was led by Mihail Nyuhitikov ....what are the other dates reffering to B-25's losses and from what airfields they took off ?